refactor: optimize plugins for angular treeshaking

BREAKING CHANGE: You can remove the plugin import from the app.module.ts because of the changed Inject decorator

src/@ionic-native/plugins/cloud-settings/index.ts

@@ -38,7 +38,9 @@ import { Cordova, IonicNativePlugin, Plugin } from '@ionic-native/core';
   installVariables: ['ANDROID_BACKUP_SERVICE_KEY'],
   platforms: ['Android', 'iOS']
 })
-@Injectable()
+@Injectable({
+  providedIn: 'root'
+})
 export class CloudSettings extends IonicNativePlugin {
   /**
    * Indicates if any stored cloud settings currently exist for the current user.